1. Field of the Invention
The present invention broadly relates to a remote-control-operated locking/unlocking system. More particularly, the invention relates to a remote-control-operated locking/unlocking system which determines the suitability of the use of a key that remotely controls a locking/unlocking unit installed in the door of a vehicle or a house, and which provides information concerning the unsuitable use of a key.
2. Description of the Related Art
Conventional types of locking/unlocking units installed in doors perform locking/unlocking operations either by being electrically powered by the remote control operation of a key or by directly inserting a key into a locking/unlocking unit and turning it.
In the locking/unlocking units that are locked or unlocked by being electrically driven by the remote control of a key, a button, for example, mounted on the key is pressed to generate a locking/unlocking signal and to drive a motor, thereby performing a locking/unlocking operation. Namely, in response to the locking/unlocking signal from the key, the suitability of the received locking/unlocking signal is determined in the locking/unlocking unit, and then, a motor serving as a driving source is driven to shift a locking/unlocking mechanism to a locking or unlocking position in a driven section.
When it is found that the locking/unlocking signal transmitted from the key is unsuitable, a locking/unlocking operation is not performed. On the other hand, when it is found that the locking/unlocking signal is suitable, a locking/unlocking operation is conducted. Whether or not the locking/unlocking signal transmitted from the key is suitable can be determined by the following manner. A rolling code contained in the locking/unlocking signal, which is variable every time a key is used, is compared with an expectation value included in the controller of the locking/unlocking unit, which value is preset to identify the key. Upon this comparison, if it is found that the matching state between the rolling code and the expectation value is within a predetermined range or conforms to predetermined rules, the operated key can be determined to be suitable. If it is desired, therefore, that the use of a certain key should be prohibited due to the loss or theft of the key, the operation panel of the controller can be actuated to erase the identification code which specifies the key from a data group. This operation prevents the execution of the locking/unlocking operation even though the key is used. Further, in addition to the identification code for identifying a group consisting of a plurality of keys, an intra-group identification code for identifying the individual keys within a specific group may be used to determine the suitability of a locking/unlocking signal transmitted from the key. Thus, the frequency of erroneous operations can be decreased.
In the above-described locking/unlocking system which performs a remote control operation with a key, security measures for locking/unlocking the locking/unlocking unit are taken against the loss and erroneous operations of the key by providing identification codes corresponding to the respective groups, each consisting of a plurality of keys. If it is found, however, that the operated key is not suitable for the locking/unlocking unit, a locking/unlocking operation is not carried out. Accordingly, the reason for a failure in performing locking/unlocking operation is unknown, and what causes the failure is not clarified, either.